This year we already know She-Ra will be one of the fandoms you may request and write for the in Yuletide challenge this year. yuletide So far Adora/She-Ra, Hordak, Shadow Weaver, and Adam/He-Man have been approved. We are currently waiting for He-Man (the show) to be approved. It usually is every year, so it probably will be again.
So, if you want to write and receive some MOTU fanfiction, check out the upcoming Yuletide deadlines!